PBDB Taxon

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Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Trionyx johnsoni

Reptilia - Testudines - Trionychidae

Taxonomy

Amyda johnsoni was named by Gilmore (1931). Its type specimen is AMNH 6357, a dermal scale, and it is a 3D body fossil. Its type locality is Telegraph Line Camp, which is in an Eocene fluvial conglomerate in the Irdin Manha Formation of China.

It was recombined as Trionyx johnsoni by Georgalis and Joyce (2017).

Sister species lacking formal opinion data

T. pliopedemontanus

Synonyms

Amyda neimenguensis was named by Yeh (1965). Its type specimen is IVPP V 2870, a partial skeleton (carapace), and it is a 3D body fossil. Its type locality is Ulan Shireh (SSPE), which is in an Eocene terrestrial horizon in the Shara Murum Formation of China.

It was synonymized subjectively with Trionyx johnsoni by Georgalis and Joyce (2017).

Synonymy list

Year	Name and author
1931	Amyda johnsoni Gilmore pp. 254-255 figs. 29; Pl. 11
1963	Amyda johnsoni Yeh
1965	Amyda neimenguensis Yeh
2008	Amyda johnsoni Brinkman et al. p. 72
2017	Trionyx johnsoni Georgalis and Joyce

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
phylum	Chordata	Haeckel 1874
subphylum	Vertebrata
superclass	Gnathostomata
—	Osteichthyes	()
subclass	Sarcopterygii	()
subclass	Dipnotetrapodomorpha	(Nelson 2006)
subclass	Tetrapodomorpha	()
—	Tetrapoda
—	Reptiliomorpha

Rank	Name	Author
—	Anthracosauria
subclass	Amphibiosauria	Kuhn 1967
—	Cotylosauria	()
—	Amniota
—	Sauropsida
class	Reptilia
—	Testudinata	(Oppel 1811)
order	Testudines	Batsch 1788
suborder	Cryptodira
family	Trionychidae	Gray 1825
subfamily	Trionychinae	Gray 1825
genus	Trionyx
species	johnsoni	()

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

†Trionyx johnsoni Gilmore 1931

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Invalid names: Amyda neimenguensis Yeh 1965 [synonym]

Diagnosis

Reference	Diagnosis
C. W. Gilmore 1931	Carapace nearly as broad as long, truncated posteriorly; seven neurals, seventh reduced; sixth costal with much expanded distal extremity; sculpture consisting of shallow sub-rounded pits, irregular in size and grouping; intervening rounded ridges narrower than pits; narrow band along lateral border devoid of sculpture.
G. L. Georgalis and W. G. Joyce 2017	“Trionyx” johnsoni can be diagnosed as a member of Pan-Trionychidae by the full list of carapacial characters provided for that clade above. Among Paleogene pan-trionychids from Asia, “T.” johnsoni can be differentiated by large size, greatly expanded distal margins of costals VII, reduced costals VIII, and a coarse sculpturing pattern.

Measurements

No measurements are available

Composition:

phosphaticsubp

Body part:

carapacef

Adult length:

100 to < 1000f

Grouping:

solitaryf

Environment:

brackish, freshwaterf

Locomotion:

actively mobilef

Life habit:

aquaticf

Diet:

piscivoref

Diet 2:

carnivoref

Reproduction:

oviparousf

Created:

2005-08-25 13:24:04

Modified:

2005-09-09 19:45:41

Source: f = family, subp = subphylum

References: Ernst and Barbour 1989, Carroll 1988

Age range: Middle Eocene or 47.80000 to 37.71000 Ma

Collections (2 total)

Time interval	Ma	Country or state	Original ID and collection number
Middle Eocene	47.8 - 37.71	China (Inner Mongolia)	Amyda johnsoni (type locality: 178831)
Middle Eocene	47.8 - 37.71	China (Nei Mongol)	Amyda neimenguensis (28792)